storage/benchfmt: use gomaxprocs as a label, not GOMAXPROCS

Change-Id: Id8fe9565bee87f824d6efbff3f983f0170534603
Reviewed-on: https://go-review.googlesource.com/34933Reviewed-by: Russ Cox <rsc@golang.org>

storage/benchfmt/benchfmt.go

@@ -124,10 +124,10 @@ func (p *Printer) Print(r *Result) error {
 func parseNameLabels(name string, labels Labels) {
 	dash := strings.LastIndex(name, "-")
 	if dash >= 0 {
-		// Accept -N as an alias for /GOMAXPROCS=N
+		// Accept -N as an alias for /gomaxprocs=N
 		_, err := strconv.Atoi(name[dash+1:])
 		if err == nil {
-			labels["GOMAXPROCS"] = name[dash+1:]
+			labels["gomaxprocs"] = name[dash+1:]
 			name = name[:dash]
 		}
 	}

storage/benchfmt/benchfmt_test.go

@@ -57,7 +57,7 @@ BenchmarkTwo 2 ns/sec
 			[]*Result{
 				{
 					Labels{"key": "value"},
-					Labels{"name": "One", "sub1": "foo", "bar": "1", "GOMAXPROCS": "2"},
+					Labels{"name": "One", "sub1": "foo", "bar": "1", "gomaxprocs": "2"},
 					2,
 					"BenchmarkOne/foo/bar=1-2 1 ns/sec",
 				},